The perovskite-type oxides, La1-xAxM1-yByO3, where A was Sr2+, Ln3+ or Ce4+, M was Fe, Co or Ga and B was Co, Fe or Mg, were prepared. Here, x ranged from 0.1 to 1, and y ranged from 0.1 to 0.5. Sub-stoichiometric compositions were also prepared. The conductivity, as a function of O partial pressures ranging from 105 to 10-14Pa and temperatures of between 500 and 1000C, was measured by using a direct-current 4-point technique and solid electrolyte coulometry. The ionic fraction of the conductivity in mixed conductors was determined by performing O permeation measurements. The II-III perovskites, Sr(Co,Fe)O3, in the stable form were very good mixed conductors; which exhibited a maximum value of 500S/cm at 400C. They also exhibited an O ionic conductivity which was up to 2 orders of magnitude higher than that of the III-III perovskite, La(Sr)Mn(Co)O3. The O ionic conductivity of the electrolyte, La(Sr)Ga(Mg)O3, could be increased by doping with 0.1mol Co. Upon using higher Co or Fe dopant additions, the lanthanum gallate became a mixed conductor.

Composition, Structure and Transport Properties of Perovskite-Type Oxides. H.Ullmann, N.Trofimenko: Solid State Ionics, 1999, 119[1-4], 1-8